It wasn't long before Roscoe was back for another sit-down. I was about to have my well-ordered universe stood on its head again.
Roscoe was much calmer this time around. "As I pointed out the last time, mostly we are going to be late. The question is, how much? Well, I think I've got a handle on it.
"As usual, the solution involves the square root, and the unit of measure is…ta da, the week. I believe that a well-managed project can be late by a number of weeks equal to the square root of the predicted number of weeks left. So when you tell me you have, for example, 16 weeks to go, I am going to assume that you will take somewhere between 16 and 20 weeks to finish."
This was getting a little deep. The square root again? How could this be? Did Roscoe not have any other tricks in his bag?
"Actually, there're five distinct cases," he went on. "I've worked it all out."
This time, Roscoe had come loaded for bear. The more he got going, the harder I listened.
"First of all, there's the well-managed project, headed by a guy who really knows what he is doing. He will be somewhere between his estimate and one square root late.
"Now, every now and then one of these gentlemen is going to do a really good job of estimating and an even better job of straw-bossing. The 'powers that be' are going to smile on him, and so on, and he will be early. Maybe even up to one square root early. It could happen." I remembered my embarrassment at not being able to come up with examples the last time we talked.
"Those are the good cases," he added.